Infrared (IR) light can cause distortions in images captured by an IR sensitive digital camera. As an example, since high temperature sources produce IR light, color distortions may appear in captured images of a scene of interest that includes one or more high temperature sources. Thus, in certain conditions, it is desirable to filter out IR light so that IR distortions can be reduced in the captured images.
However, IR light is sometimes used to provide illumination in low lighting conditions when a conventional flash of light is inappropriate. Thus, some digital cameras include one or more IR light emitting diodes (“LEDs”) to produce IR light in addition to a conventional flash. When using IR light for illumination, it is obviously not desirable to filter out IR light.
Since IR light filtering is desired in certain conditions and not in others, a removable IR filter is commonly used to selectively filter IR light. The removable IR filter is designed to fit over the lens of a digital camera to block IR light so that IR light does not reach the image sensor of the camera. When using IR light for illumination, the removable IR filter is removed to allow IR light to be transmitted to the image sensor.
A concern with the use of a removable IR filter is that a digital camera must be designed to accommodate the removable IR filter, which may be difficult for some camera types such as a camera phone. Furthermore, the accommodation of the removable IR filter may inhibit development of more compact digital cameras. Another concern is that a removable IR filter may be difficult to remove from the digital camera in dark conditions, and may be lost when removed from the camera.
In view of these concerns, there is a need for an IR sensitive digital camera and method for producing IR filtered digital image of a scene of interest without the use of a removable IR filter.